A phased array ultrasonic sector scanner (PAUSS) will be used to image the left ventricle in several planes in patients with symptomatic coronary artery disease for correlation with the contrast ventriculogram and coronary arteriogram. Assessment of the degree of accuracy of the PAUSS for identifying asynergy compared to the contrast angiogram will be made. Additional comparison will be made of the results of this investigation both with the abnormalities on graded exercise tests and with radionuclide angiograms by the first pass method. In vitro test of resolution of the instrument in all three planes as well as its practical use for measuring muscle thickness in the plane of image and when the muscle section is oblique to this plane will be made. Pre and postoperative coronary artery bypass graft surgery studies will be compared to observe changes in wall motion and myocardial contraction resulting from surgery. Open chest dogs will be studied using this device both before and after ligation of small coronary vessels to create segmental wall motion abnormalities. These animals will have contrast angiography and some will have placement of intramyocardial clips. Comparison will be made of asynergy detected by the PAUSS and these methods. The clip studies will define correspondence of myocardial segments by the PAUSS and contrast ventriculogram.